Arc converter



Dec. 16, 1924. 1,519,398

H. F. ELLIOTT ARC CONVERTER Filed Dec. 14, 1921 WITNESS INVENTOR WW HAROLD FiELuoTT.

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74a ATTORNEYS Patented Dec. 16, i924.

UNITED STATES inane PATENT OFFICE.

HAROLD IE. ELLIOTT, OF T ALO ALTO, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGKL MENTS, TO FEDERAL TELEGRAPH COMPANY, OF SAN GOR'PORATION OF CALIFORNIA.

FRANCESCO, CALIFORNIA, A

ARC CONVERTER.

Application filed December 14, 1921. Serial No. 522,336.

To all whom it may concern:

Be it known that I, HAROLD l3. ELLIOTT, acitizen of the United States, and a resident of Palo Alto, in the county of Santa Clara and State of California, have invented a new and useful Arc Converter, of which the following is a specification.

My invention relates to the operation of arc converters, such as the Poulsen arc, used for converting electrical energy in the form of direct current or low frequency alternating current, into electrical energy in the form of radio frequency current. More particularly my invention relates to an are converter which is operated in an atmosphere of hydrogen or other gas having similar electro-mechanical properties.

The operation of such arcs is more satisfactory when pure gas such as hydrogen is used, undiluted by other gases. Not only are the operating characteristics of the arc impaired, but explosions may also; result when air or oxygen is commingled with the hydrogen. The harmful mixture may be brought about at the time the arc chamber is filled with hydrogen preparatory to its operation or after an old charge of the gas is expelled, since the chamber, if no extra precautions be taken, usually has left 1n t, prior to refilling, a small amount of air. It is one of the objects of my invention to obviate such an occurrence, and thereby to insure eflicient and safe operation. Another object is to make it possible to maintain the arc chamber clean and free from any carbon deposit.

The invention possesses other advan tageous features, some of which, with the foregoing, will be set forth at length 111 the following description, where I shall outline in full that form of the invention which I have selected for illustration in the drawing accompanying and forming part of the present specification. In the drawing I have shown one embodiment of my invention, but it is to be understood that I do not limit myself to that form, since the invention as expressed in the claims may be embodied in other forms as well.

The single figure illustrates diagrammatically an apparatus embodying my invention. The are chamber or container 1 is preferably cast and made with a jacket 2 for the accommodation of cooling water. The

interior 8 of the chamber 1 holds the hy drogen or other gas and accommodates the electrodes 5. Magnetic field poles 4: projecting through the sides of the chamber 1 infiuence the arc in a well-known manner. The gaskets 6 serve to render the enclosure gas-tight.

Means are provided for pumping out the used gas and supplying new gas to the interior 3 of the chamber. Thus the piping '7 connects the chamber with a vacuum pump 9. During the process of exhaustion by this pump, the chamber is not in communication with any external gas source. For effecting this, the pipe 8 which connects the chamber with a gas reservoir 17, is provided with a valve 16. This valve is kept closed while pump 9 is exhausting. All connections to the chamber must of course be gas tight. In order to prevent excessive pressures within the chamber during operation, a poppet valve or relief valve 15 is provided somewhere in the pipe 7. A combined pressure and vacuum gauge 14- indicates how far the exhaustion is carried, and after a sufficiently good vacuum is obtained, the pump 9 may be rendered inactive. Then the valve 10 may be turned to disconnect the pump 9 from the pipe 7 and to close up the end of this pipe so as to make the chamber air tight.

A surge chamber 12 connected to pipe 7 through a valve 13 is shown, and serves as a reservoir to prevent large variations in pressure which would otherwise result from the variations in temperature attendant upon the starting and stopping of the are. An alternate device for effecting this result is also shown, consisting of a gas seal 19 connected to a pipe 7 through the valve 18. This form may be used for operating the arc with an envelop of gas at atmospheric pressure. The gas seal 19 is formed with an Lip-standing goose neck portion and preferably the volume of this seal should be large enough to serve also as a surge chamber. The operation and construction of such a device is described and claimed in a pending application in the name of Ralph E. Beal, entitled Arc converters, Serial No. 402,928, tiled August 11, 1920.

Upon operation of the are for a long period there is a tendency for a carbon delllll posit in the form of soot to accumulate. To clean this accumulation outexpeditioue 1y, I provide a blower 11 or its equivalent,

which. may. be connected. to-pipe 7 by turning valve 10;. The door of the arc chamber may be opened after such a period of' operation, and the blower operated for a short time. The soot may then easily be removed; After this is accomplished, the chamber may be closed and the pump 9 used: to: exhaust all of the air.

The mode of operation of" the invention may now'be-mad'e more apparent. It there is any deposit which it is desired to clean out, valve 10 is turned to connect blower 1 1 with pipe 7, valves 16, 1-6, 13 and 18 are closed, the door of the arc chamber 1 is opened, and the blower 11 is operated until all: the soot or othcrdeposit isblown out. Then blower 11 isstopped, the door of the chamber is closed, valves 1-6 and 18 remain closed, and: valve 10 turned to the position shown so as toconnect pump 10 to the chamber; The pump is then operated. until a' suflicient degree or vacuum is obtained, after which thepump is stopped. Valve l0 may then be turned to shut the end of pipe 7, and valve 16 opened tofill the chamber 1 with gas from a source 17, until suflicient pressure is obtained. During the process of exhaustion, valve 13 should be either open or closed, depending upon whetherthe Chamber 12 contains air or diluted gas, or whether it already contains. hydrogen. During; ordinary operation: ofthe arc, it isprefi'erable to use the surge chamber 12 instead of-the gas seal 19.

I claim;

1. In an, arc converter,. an. arc chamber, a pump for exhausting the chamber, a blower, and. a single means arranged to connect either the pump or blower with the arc chamber. Y

2. In an arc converter, an arc chamber, a pump for exhausting the chamber, a blower, and a valvearranged s0= as toplace either the blower or the pump in connection with the chamber. 1

3. In an arc converter an arcchamber, a pump for exhausting the chamber, a blower, and a valve soarranged that it may seal the chamber or else connect eitherthe blower or thepumptheretm V 41+. In an arc converte-r, an. arc. chamber, pipe leadingfrom the arc chamber, a pair of branch pipes connected to saidr pipe, said branches connecting to the pipe at a common point, a pump for exhausting the chamber connected to one of the branches, a blower connected to the other, and? a. valve located at the comm orr point; and adapted to connect either of the branches with the pipeleading from the-arc chamber;

In testimony whereof, I have hereunto set my'hand;

HAROLD F; ELLIOTT- 

